Common Peroneal Nerve

nervus peroneus communis

The common peroneal nerve (common fibular nerve, L4-S2) is the lateral division of the sciatic nerve, winding around the fibular neck to divide into the superficial peroneal nerve (lateral compartment muscles, dorsal foot sensation) and deep peroneal nerve (anterior compartment, first web space). It is the most commonly injured nerve in the lower limb due to its superficial course around the fibular head.

Region: Knee

Clinical Relevance

Clinical Notes

Common peroneal nerve palsy at the fibular head produces foot drop (weak dorsiflexion and eversion) with loss of dorsal foot sensation. Causes include fibular head fracture, prolonged squatting, tight plaster cast, and knee dislocation. EMG localises the lesion to the fibular head and distinguishes it from L4-L5 radiculopathy (which additionally affects hip abductors and hamstrings). Ankle-foot orthosis (AFO) manages foot drop. Surgical decompression at the fibular neck is indicated for compressive lesions. Tibialis posterior tendon transfer to the dorsum restores active dorsiflexion in permanent palsy.

Pathology

Common Injuries & Conditions

Common Peroneal Nerve Palsy

Foot drop with dorsal foot sensory loss from fibular neck compression — distinguished from L4/L5 radiculopathy by normal knee reflex and nerve conduction studies.